Vold now does not check caller's permission, but only accepts
transactions from system_server. And it's up to system server to do the
right thing and check permissions/appops.
Bug: b/152633648
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest
Test: adb shell appops set 1000 GET_USAGE_STATS deny
Change-Id: Id56c1673b135b72b3ec86e572aa4bcca3afc19ab
+ Get rid of an extra string copy in path validation function
Bug: 152349257
Test: atest vold_tests
Change-Id: I03a8cab0dd6abd7d5c9dcbbc2acb651e818e6cd8